Source code for pygmt.src.grdclip

grdclip - Change the range and extremes of grid values.

from pygmt.clib import Session
from pygmt.helpers import (
from import load_dataarray

__doctest_skip__ = ["grdclip"]

[docs]@fmt_docstring @use_alias( G="outgrid", R="region", Sa="above", Sb="below", Si="between", Sr="new", V="verbose", ) @kwargs_to_strings( R="sequence", Sa="sequence", Sb="sequence", Si="sequence", Sr="sequence", ) def grdclip(grid, **kwargs): r""" Sets values in a grid that meet certain criteria to a new value. Produce a clipped ``outgrid`` or :class:`xarray.DataArray` version of the input ``grid`` file. The parameters ``above`` and ``below`` allow for a given value to be set for values above or below a set amount, respectively. This allows for extreme values in a grid, such as points below a certain depth when plotting Earth relief, to all be set to the same value. Full option list at :gmt-docs:`grdclip.html` {aliases} Parameters ---------- grid : str or xarray.DataArray The file name of the input grid or the grid loaded as a DataArray. outgrid : str or None The name of the output netCDF file with extension .nc to store the grid in. {R} above : str or list or tuple [*high*, *above*]. Set all data[i] > *high* to *above*. below : str or list or tuple [*low*, *below*]. Set all data[i] < *low* to *below*. between : str or list or tuple [*low*, *high*, *between*]. Set all data[i] >= *low* and <= *high* to *between*. new : str or list or tuple [*old*, *new*]. Set all data[i] == *old* to *new*. This is mostly useful when your data are known to be integer values. {V} Returns ------- ret: xarray.DataArray or None Return type depends on whether the ``outgrid`` parameter is set: - :class:`xarray.DataArray` if ``outgrid`` is not set - None if ``outgrid`` is set (grid output will be stored in file set by ``outgrid``) Example ------- >>> import pygmt >>> # Load a grid of @earth_relief_30m data, with an x-range of 10 to 30, >>> # and a y-range of 15 to 25 >>> grid = pygmt.datasets.load_earth_relief( ... resolution="30m", region=[10, 30, 15, 25] ... ) >>> # Report the minimum and maximum data values >>> [,] [179.0, 2103.0] >>> # Create a new grid from an input grid. Set all values below 1,000 to >>> # 0 and all values above 1,500 to 10,000 >>> new_grid = pygmt.grdclip( ... grid=grid, below=[1000, 0], above=[1500, 10000] ... ) >>> # Report the minimum and maximum data values >>> [,] [0.0, 10000.0] """ with GMTTempFile(suffix=".nc") as tmpfile: with Session() as lib: file_context = lib.virtualfile_from_data(check_kind="raster", data=grid) with file_context as infile: if (outgrid := kwargs.get("G")) is None: kwargs["G"] = outgrid = # output to tmpfile lib.call_module("grdclip", build_arg_string(kwargs, infile=infile)) return load_dataarray(outgrid) if outgrid == else None